Experimental design for the functionalization of activated carbon as catalyst in Catalytic wet air oxidation of phenol Maretva Baricot Mendoza Supervisor Dr. Josep Font Capafons Chemical Reaction Engineering and Process Intensification Group, Department of Chemical Engineering, Universitat Rovira i Virgili Tarragona, February 3rd 2005

Content Introduction State of the art Objectives Methodology Expected Results Future work 2/13

Introduction Environmental problem Treatments Adsorption Membranes Filtration Ultrafiltration Reverse osmosis Chemical Oxidation Biological Treatments 3/13

Introduction Activated Carbon What is it ? Growing interest!!! Carbonaceous materials, highly crystalline form Extensively developed internal pore structure Growing interest!!! Adsorption, catalyst support but lately….. As catalyst itself!!! 4/13

State of the Art Characterization of carbon surface Chemical titrations Temperature programmed desorptions Infrared and X-ray photoelectron spectroscopy Most common functional groups Phenolics Carbonyls Carboxyls Quinones Lactones Anhydrides 5/13

State of the Art Functional groups Carboxylic acid Lactone Phenol Carbonyl Anhydride Ether Quinone 6/13

Environ. Sci. & Technol, 2002. 36(17): p. 3844-3849 State of the Art Modified AC Herbicides Baçaoui et al Environ. Sci. & Technol, 2002. 36(17): p. 3844-3849 Pereira et al Appl. Catal., A, 1999. 184(1): p. 153-160 Activated carbon as catalyst in the oxidative dehydrogenation of ethylbenzene 7/13

Commercial activated carbon State of the Art CREPI Phenol oxidation in a Trickle bed reactor (TBR) @ 160ºC and Oxygen partial pressure 0,82 MPa(1) Conversion up to 99 % Commercial activated carbon as Catalyst (1) J. Chem. Technol. Biotechnol., 2001. 76(7): p. 743-751 8/13

Objectives Main Secondary Design an experimental procedure to functionalize activated carbon in order to obtain a good surface chemistry that improves the catalytic activity of carbon in the TBR. Secondary Superficial functional groups Carbon texture Defunctionalization-Refunctionalization process 9/13

Methodology Carbon treatment Defunctionalization Heat treatment under Inert atmosphere Elimination of surface functional groups Temperatures ranges Refunctionalization Heat treatment under Oxygen and Nitrogen atmosphere Formation of specific surface functional groups Varying T, PO2 and time 10/13

Methodology MAC tests Set of Modified Activated Carbon MAC From Refunctionalization Stage Set of Modified Activated Carbon MAC MAC tests Adsorption tests Catalytic activity tests Batch configuration TBR, Milder conditions 11/13

Methodology MAC characterization From the set of MAC those that shows better performance as catalyst and adsorptive material… MAC characterization Chemical titrations TGA + TPD Infrared Spectroscopy Thermogravimetric analysis + Thermal programmed desorptions 12/13

Expected Results Clarification of the influence of the surface chemistry on the AC catalytic performance Determination of better surface chemistry on activated carbon for it to show catalytic activity Obtaining a better catalyst for phenol oxidation than commercial AC Procedure to design tailor made AC active for CWAO, from any source 13/13

Future work Develop an experimental procedure combining oxidizing treatments and characterization techniques to obtain catalyst useful in oxidation of several compounds as halogenated phenols Improve adsorptive performance of AC with chemical surface modification Establish experimental procedures to specifically functionalize AC surface in order to improve its behavior as catalyst, support or adsorptive material 14/13

Questions Thanks for your attention!!! ???? Questions